Ratories



ug 27 c. A. BRIGHAM 1638320- INV EN TOR.

Aug. 9, 1927.

C. A. BRIGHAM SOUND REPRODUCING APPARATUS 2 ShntsQSheet 2 Filed Nov. 2. 1926l Patented Aug. 9, 1927.

` UNITED STATES PATENT OFFICE.

CYRIL A. REIG-HAM, F EAST ORANGE, NEW JERSEY,v ASSIGNOR TO BRANDES :LABOm RATORIES. INC., OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SOUND-REPRODUCING APPARATUS.

Application led November My invention relates broadly to elect-roniagnetic sound reproducers and more particularly to a construction oit electromagnetic' is to cone with an electromagnetic driving` member secured thereto. p

Another obJect oit my invention is to provide a construction of bridle or connecting means between the electromagnetic driving element and a cone shaped sound reproducing diaphragm.

Another object ot my invention to provide a link connection between a conical shaped sound reproducing diaphragm and electromagnetic driving element which connection is independent and remote from the apex ci? the conical shaped sound reproducingI diaphragm.

Other and 'further objects ot Amy invention will be understood from the specification hereinafter following by reference to the accompanying drawings inwhich:

Figure 1 is a iront view illustrating the assembly ot the sound reproducing diaphragm and electromagnetic driving element of my invention; Fig. 2 is a plan view ot the sound reproducing diaphragm showing the connection of the electromagnetic driving element thereto, the diaphragm being partially broken away and illustrated in section; Fig. 3 is a cross-sectional view taken" through the electromagnetic driving mechanism and sound reproducing diaphragm of my invention; Fig. 4 is a lateral crosssectional view of the sound reproducer of my invention taken on line 4 4 ot Fig. 3; and Fig. 5 is a perspective view showing the parts of the bridle element by which connection is established between the electromagnetic driving element and the sound reproducing diaphragm.

My invention relates particularly to the class of electromagnetic sound reproducers illustrated in my copending application, Serial Number 135,192, tiled September 13, 1926.

Referring to the drawings in detail, I have illustrated the sound reproducer as comprising a panel 1 in which the conc shaped sound reproducing diaphragm 3 is 2, 1926. Serin Noj 145,808.

arranged to float, the peripheral edge 4 ot the sound reproducing diaphragm being connected to the plate 1 by means of an annular strip 2f The sound reproducing diaphragm is substantially in the form ot a trustum oi a cone terminating at a small diameter 5. Embracing the small diameter 5 of the cone -I provide a pair of semi-circular members G and 7 which conform to the peripheral edge 5 of the cone with stripdike eXtensions 6, 6b and 7a, 7" extending in a plane passing through the axis oit the cone. The driving mechanism ot' the cone consists of a pair of windings 1() and 11 which are secured to opposite sides oit the tiat coil support 8; The coil support 8 is constructed ot insulating material which is ot extremely light weight by reason ot cut away portions 9. A pair of extensions or arms 8a and Sb are formed on the coil support S with their ends cut away'to contorni to the shape o't the sound reproducing diaphragm 3 and formed in such manner that the strip-like extensions, 6, 6b, "2 and 7" are arranged to `grip opposite sides of the extensions t" and 8 forming a rigid connection between the coil 5 and the cone-shaped diaphragm. The spider member 12 is suspended :from the strip member 14 which isin turn attached to the trame 15 of the 'loud speaker. The loud speaker is provided with an electromagnetic system including sets of pole pieces 16 and 17 which may be provided with face plates 18 and 19 for rendering the reproduction more uniform as described in my aforementioned application. The strip member 2O is secured to the opposite side of frame 15 and is apertured to permit the free passage of the coil support 18 therethrough. The spider 12 connects with the coil support 8 as represented at 21 and 22 in such manner `that the sound reproducing diaphragm 4 and the windings 10 and 11 substantially float between the frame 1 and the strip 'member 14. It will be observed thatthe windings 10 and 11 are free to move in a lateral direction between the Sets of pole pieces without inertia, the coils being confined in a path parallel to the pole pieces and at right angles to the magnetic lines of force passing between the pole pieces.

Y inga laterally movable element, means for the efficient transfer of mechanical vibrations from the coil support to the sound reproducing diaphragm.

" The preferred embodiment of `my invention described inl theV drawings hasbeen foundl to be extremely practical and efficient in operation, but I desirefthat it be understood that modiiications may be made and that no limitations uponV my invention are vintended other'thanmare imposed by the scope ot the appended claims.

What I claim as. new and desire to secureV secured: at diametrically opposite points to said flat coil structure. v

2; A soundreproducer comprising a sound reproducing diaphragm substantially in the shape of the rustuin ot cone, an aperturcd platemember encircling the peripheral edgeY of: said soundreproducing diaphragm at the largest diameter ,thereon means connecting `the peripheral edge of said' sound Yreproducing diaphragm with said; plate member, "an electromagnetic drivingv mechanism includ suspending said laterally movable element at one end thereof lor free movement 1n the vdirection' of said sound' rreproducing dia-v phragm and a connection between tvvo separated points on said 'laterally movable element *andA said soundfreproducin'g diaphragm whereby vibrations imparted to said lateralf lyv movable element may be transferred to said sound reproducingl diaphragm,

3. A sound re roducer com rlsm asound reproducing diaphragm substantiallyY in they shapel ciZ the frustuni of a cone, an electromagnetic driving mechanism including a Y movablecoil structure located along the `axis oit said sound reproducing diaphragm, a connection between separatedpoints on ksaid movable coil structure and separate points on said soundv reproducing diaphragm on diainetrically opposite sides oit the center thereofz, and meansfor flexibly suspending the peripheral edge of said sound reproducing diaphragm and one end of said movable coil structurewhereby .vibrations imparted te said movable coil structure may be transferred kto said sound reproducing dia.- phragm.

4L. A sound reprodu'cer comprising a sound reproducing diaphragm substantially in the shape et the i'rustum ot a cone, an. electro-V magnetic driving mechanismincluding an element movable' in the direction of the axisV otsaid sound reproducing diaphragm7vmeans for flexiblyl suspending said' movable element and said sound reproducing dia-` v'phragin, a pair ot arms extending from said movable element and engagingsaid sound reproducing diaphragm at diametrically 0p-V posite points thereonand a pair 'of semi-cir# cular strip members secured to, said sound reproducing diaphragm andy connecting opposite sides of said arms whereby vibrations` initiated: in said movable element ymay be Y transferred to said sound reproducing diaphragnn Y v Y 1 In testimony whereoi I ailiX mv signature.

ovni-n A. 'BRIGHAM 

